Safety apparatus for lowering tower equipment

ABSTRACT

Safety apparatus to protect against failure of a winch cable in lowering a tower mounted light fixture frame normally suspended by several suspension cables extending downwardly through the tower, including a pair of stationary cables in the tower and extending from bottom to top; a safety appliance sliding along such safety and guide cables and interconnecting the suspension cables to the winch cable and including a friction gripping mechanism sliding along one of the safety cables and normally held out of locked condition by the tension load transmitted between the winch cable and the suspension cables; and including spring connections between the safety appliance and the winch and suspension cables.

titted tates tet [191 Latanision 1 Oct. 8, 1974 SAFETY APPARATUS FORLOWERING TOWER EQUIPMENT [75] Inventor: Myron Thomas Latanision, Red

Wing, Minn.

[73] Assignee: Meyer Industries, Inc., Red Wing,

Minn.

[22] Filed: Dec. 27, 1972 I 21 Appl. No.: 318,724

[52] US. Cl 254/139, 182/112, 187/73, 240/88 [51] Int. Cl B66d 1/28 [58]Field of Search 254/135, 190 R, 144, 145, 254/139; 187/81, 73, 71, 89;240/63, 64, 67, 69, 84, 88;182/14l,142, 143,150,112

[56] References Cited UNITED STATES PATENTS 1,043,323 ll/l9l2 Lester187/81 3,686,498 8/1972 Meyer 240/88 X FOREIGN PATENTS OR APPLICATIONS185,678 9/1922 Great Britain 187/81 212,710 3/1924 Great Britain...187/81 OTHER PUBLICATIONS Advertising Brochure from Osram (G.E.C.)Street Lighting Limited, 3 pages, 9/1968.

Primary Examiner.lames B. Marbert Assistant Examiner-James L. RowlandAttorney, Agent, or Firm-H. Dale Palmatier [57] ABSTRACT Safetyapparatus to protect against failure of a winch cable in lowering atower mounted light fixture frame normally suspended by severalsuspension cables extending downwardly through the tower, including apair of stationary cables in the tower and extending from bottom to top;a safety appliance sliding along such safety and guide cables andinterconnecting the suspension cables to thewinch cable and including afriction gripping mechanism sliding along one of the safety cables andnormally held out of locked condition by the tension load transmittedbetween the winch cable and the suspension cables; and including springconnections between the safety appliance and the winch and suspensioncables.

9 Claims, 4 Drawing Figures PATENIED 81974 3840212 SHEET 10F 2PATENTEnum 81974 SHEEI 2 [IF 2 SAFETY APPARATUS FOR LOWERING TOWEREQUIPMENT BACKGROUND OF THE INVENTION In illuminating highwayintersections and other larger spaces such as parking lots, it has beenfound desirable to use towers which are quite high, from 90 to 150 feetor more in height. By use of towers of such height, the number of towersneeded to illuminate a large area is considerably reduced. The actuallamps are carried on a fixture frame which is suspended by cables frompul- Ieys at the top of the tower and may be lowered to the ground sothat the lamps may be easily serviced. Lowering the fixture frameandlamps to the ground is an alternative to having a workman climb to thetop of the tower to service the lamps.

Of course, by allowing the workman to remain on the ground and bylowering the fixture frame and lamps to the ground, the likelihood ofinjury-to the workman is materially reduced. However, there is someinherent danger in lowering such fixture frames and lamps from highelevations to the ground, because there is always the possibility ofbreakage or rupture of a winch cable which is used for lowering thefixture frame and lamps to the ground.

In the ordinary construction of the tower, there are several pulleysprovided at the top of the tower and several suspension cables whichfunction to continuously suspend the fixture frame and hold it upwardlyagainst rigid crossarms at the top of the tower. The suspension cablesextenddown through the tower and are normally attached to acounterweight at the bottom of the The present invention utilizes a pairof guide cables in the tower which are anchored at both the top andbottom ends. Asafety appliance isconnected to the suspension cables andis also connected to the winch cable for transmitting the tension loadbetween the winch cable and the suspension cables during lowering of thefixture frame. The safety appliance also guides along the largeelectricalcable, one end of which is attached to the fixture frame forsupplying electrical energy to the lamps on the fixture frame, and theother end of the cable is ordinarily connected to a power source at thebottom of the tower, but is disconnected and moved upwardly in the towerwith the suspension cables during such time as the fixture frame isbeing lowered.

The appliance incorporates a quick setting clamp to grip-one of thesolidly anchored guide cables in the tower in the event of a rupture orfailure of the winch cable so that the appliance is securely anchored atafixed location in the tower and the fixture frame is prevented fromdropping freely. The suspension cables are connected to the appliance byspring connections so that when the appliance suddenly grips the guidecable in the tower, the tension load is applied to the suspension cablesquickly, but not absolutely instantaneously, and therefore thesuspension cables are prevented from snapping due torapid application ofload.

The clamping shoe is moved into locking engagement failure of the winchcable, and the spring causes the tower so that tension on the suspensioncables is maintained at all times.

When the fixture frame is to be lowered, a winch is inserted between thecounterweight and the suspension 7 cables, and, as the winch cable ispayed out, the counterweight will first be lowered onto a solid rest atthe bottom of the tower and then the suspension cables are allowed tomove upwardly through the tower and then over the pulleys for allowingthe fixture frame to be lowered at the outside of thetower.

Several suspension cables are utilized so that the fix- .ture frame isbalanced, and is prevented from swaying due to wind, and the use ofseveral substantially parallel suspension cables prevents anypossibility of allowing the fixture frame and the lamps to drop due torupture of a suspension cable because there are always several BRIEFSUMMARY OF THE INVENTION Accordingly, the present invention is addressedto preventing or minimizing the likelihood of any damage occurring intheevent that the winch cable should fail during lowering of the fixtureframe along a hightower.

The present invention consit'utues safety apparatus to be mounted in atower and utilized in connection with the winch cable so as toimmediately assume the weight of the fixture frame and hold the fixtureframe in the event that the winch cable should fail.

clamping shoe to very rapidly grip the guide cable but does not causethe appliance to stop absolutely instantaneously on the guide cable (notas a pawlwould stop against a rachet tooth), to at least slightly lessenthe rate of application of the load to the guide cable.

BRIEF DESCRIPTION OFTHE DRAWINGS DETAILED DESCRIPTION OF THE INVENTIONOne form of the invention is illustrated in the drawings and isdescribed herein.

The safety apparatus comprising the present invention is indicated ingeneral by numeral 10 and is intended for use within the tubular pole 11for supporting lamps 12 mounted on a fixture frame 13 which is normallydisposed at the top of the tower but which may be lowered on itssuspension cables 14 to the ground for servicing the lamps 12. Thislighting tower is particularly designed for use in illuminating highwaytraffic interchanges and intersections, large parking areas and thelike. The pole 11 may be feet high 'or higher. The pole II has crossarmsl5 projecting outwardly from its top, and pulleys are mounted at the topof the pole I] and in the arms 15 for guiding the suspension cables 14from within the tubular pole 11 to the fixture frame 13.

In the normal condition of the tower, the suspension cables 14 areentirely confined within the tubular pole 11 and the crossarms l5, andthe suspension cables 14 serve to carry 'a counterweight 16 which morethan offsets the weight of fixture frame 13 and lamps 12 so as to pullthe fixture frame tightly up against the crossarms 15. As illustrated inFIG. 1, the counterweight 16 has a winch 17 affixed on its top, and thewinch 17 has a winch cable 18 to carry the same tension load carried bythe several suspension cables 14. Normally the counterweight 16 issuspended by the cables and off the base of structure of the tower. Whenthe fixture frame 13 is to be lowered, the winch 17 will pay out thecable 18 and the first effect of this is to lower the counterweight 16to the base of the tower which will thereafter support thecounterweight. Subsequent operation of the winch 17 pays out-additionalcable to effect the lowering of the fixture frame 13.

The safety apparatus includes a pair of safety and guide cables 19 and20, and a safety appliance which is indicated in general by numeral 21for interconnecting the suspension cables 14 and the winch cable 18 andtransmitting the tension load therebetwen. Normally the safety appliance21 will slide freely along the guide and safety cables 19, 20, which areaffixedly anchored to the tower at its bottom and top and are stationarywithin the pole 11. In, the event that the winch cable 18 should fail,the safety appliacne 21 will immediately clamp onto the safety cable 19and will stop to prevent any uncontrolled travel of the suspension cable14 upwardly through the pole 11 and falling of the fixture frame 13 andlamps 12 is thereby prevented.

The safety appliance 21 includes a pair of upper and lower rigid frameplates 22 and 23 which are rigidly interconnected by a pair of posts 24and 25 which are welded to the upper and lower frame plates. The frameplates have rather large aligned openings 22.1 and 23.1 for receivingand retaining a multiple conductor electrical cable 26 which extendsentirely to the top of the tower and supplies power tothe lamps 12.

The frame plates also have aligned bearing or guide apertures oropenings. 22.2, 23.2 which receive and freely pass the guide and safetycables 19, and maintain these cables in side by side relation.

The safety appliance 21 makes provision for a resilcables 14, andaccordingly, a plurality of rigid slide bars 27 are slidably mounted inopenings 22.3 in the upper frame plate 22. These openings 22.3 aresymmetrically and uniformly disposed around the periphery of the frameplate 22 for equal distribution of the load onto the frame plate fromthe suspension cables 14. The upper ends of the slide rods 27 aresecured to connector fittings 14.1 on the ends of cables 14 by bolts27.1.

The lower portions of the slide rods 27 below the frame plate 22 havecompression springs 28 thereon. The springs 28 b'ear upwardly againstthe frame plate 22 and urge the slide rods 27 downwardly and bearagainst washers 27.2 and threaded nuts 27.3 threaded onto the lower endsof the rods 27.

A slide bar or rod 29 is provided for connecting to the winch cable 18and is slidably mounted in an oblong shaped opening 23.3 in the lowerframe plate 23. The opening 23.3 is located at the center of frame plate23 and is oriented with the longest dimension of the oblong openingextending substantially toward the iently yieldable connection to eachof the suspension guide and safety cable 19 and the opening 23.2 throughwhich it extends so as to permit limited movement of the rod 29 towardand away'from the guide and safety cable 19. The lower end of the slidebar 29 is connected 'to a fitting 18.1 on the end of cable 18 by meansofa pin or bolt 29.1. A portion of the slide rod or bar 29 is disposedabove the lower frame plate 23, and this upper portion of the rod 29 isencompassed by a compression spring 30 which bears downwardly againstthe frame plate 23 and bears upwardly against the bifurcated head 29.2which is affixed on the upper end of rod 29. The spring therefore urgesthe rod 29 upwardly against the tension exerted by the winch cable 18,and as illustrated, the spring 30 is ordinarily compressed so that theconvolutions of the spring bear against each other when the appliance 21bears the tension load between winch cable 18 and the suspension cables14.

A rigid U-shaped clamp body 31 is formed of heavy gauge steel and isaffixed as by welding to the upper and lower frame plates 22 and 23 withthe closed side 31.1 of the U-shape located adjacent the peripheries ofthe frame plates and defining a cable-guiding passage 31.2 confining theguide and safety cable 19 and extending between the apertures 22.2 and23.2 in the frame plates and which guide the cable 19. The U- shapedclamp body 31 has its open side facing the rod 29 to receive clamp bar32 therein. Clamp bar 32 is mounted on pivot 33 which is carried inapertures in the side plates 31.3 of the clamp body 31. The clamp bar 32extends out of the open side of clamp body 31 and has its attachment end32.1 connected by pivot 29.3 to the bifurcated head 29.2 of the slidebar or rod 29. The inner end of clamp bar 32 defines a clamping shoe32.3 which is rounded and which is knurled or roughened in confrontingrelation with the cable 19 and the cable-guiding passage 31.2 of theclamp body 31. The inner end of the clamp bar extends obliquely towardthe cable 19 and somewhat upwardly whereby upward swinging of the innerend of clamp bar 32 will cause the clamping shoe 32.3 to swing away fromthe cable 19, and downward swinging of the shoe 32.3 will cause it toengage and clamp against the cable 19.

The closed side 31.1 of the U-shaped clamp body 31 defines a clampingjaw, along the passage 31.2, which cooperates with the clamping shoe32.3 of the clamp bar to grip the cable 19 and prevent upward movementof the appliance 21 along the cables.

Normally, while the light fixture frame 13 and lamps 12 are disposed atthe top of the tower, the safety appliance 21 is located at the bottomof the pole 11, substantially as illustrated in FIG. 1. The tension loadfrom the suspension cables 14 is translated to the winch cable 18 by thesafety appliance 21. In this condition, the spring 30 will besubstantially completely compressed so that the convolutions of thespring will bear against each other; and in this condition, the-rod 29will have pulled the end of clamp bar 32 downwardly so that the clampingshoe 32.3 will have swung upwardly away from the cable 19. Thereforethere is no interference to sliding-by the appliance along the cables 19in the event that the winch 17 is operated to pay out the winch cable18.

While the safety appliance 21 is in stationary condition at the bottomof the pole 11, the springs 28 on the slide rods 27 which serve toconnect the suspension cables 14 to the appliance frame, aresubstantially completely compressed.

When the lamps 12 and the fixture frame 13 are to be lowered to theground for service, the electric supply cable 26 may be disconnectedfrom the power source near the bottom-of pole 11 and then the winch 17will be'operated to pay out the winch cable 18. Initially, thecounterweight 16 is lowered to the base-of the tower to be supportedthereon; and thereafter,further unwinding of winch cable 18 fromthe'winch drum allows the safety appliance 21 and the lower ends ofsuspension cables 14-to move upwardly through the pole 11. Accordingly,the lamps 12 and fixture frame 13 will be'lowered toward the ground,substantially as shown'in dotted lines in FlG. 1.

Whereas there are three separate suspension cables 14,-any of which isstrongenough to carry the entire weight of the lamps 12 and fixtureframe 13, there is little concern for the failure of one of thesuspension cables14.- v

However, if the winch cable 18 should fail, the lamps 12 and fixtureframe 13 will fall from the top of the tower, but for the safety devicewhich includes the fixed cable 19, 20, and the safety appliance 21. I

In the event the winch cable 18 fails, or breaks, the safety appliance21 no longer will carry the tension 'load that it previously did whenthe winch cable is intact. As a result of this loss of tension load, theappliance will immediately lock against the cable 19 and be preventedfrom traveling upwardly in the pole 11 so as to prevent the lamps andfixture frame from falling.

More specifically, when the winch cable fails, the

spring 30 will move the slide bar 29 upwardly and by the springs 28 isimmediately relieved when the winch cable 18 ruptures or fails. As aresult, the springs 28 tend to expand under the reduced load and movethe slide rods 27 downwardly in theappliance frame.

When the appliance 21 locks onto cable 19, a tension load is once againapplied to the suspension cables 14 to stop the falling of the lamps andfixture frame. The springs 28 compress again, and slightly reduce therate of stopping of the suspension cables 14 and the fixture frame 13 ascompared to the rate at which the frame of appliance 21 is stopped alongthe cable 19. Therefore, instead of stopping the suspension cables 14absolutely instantaneously (as if to be stopped by a pawl against aratchet tooth), the suspension cables and the fixture frame are stoppedsomewhat gradually, which has the effect of reducing the shock loadingof the suspension cables and reducing the likelihood of snapping orbreaking of one of the suspension cables due to extremely high rate ofapplication of load.

Of coures, the resilient yielding of springs 28 as the tension load isapplied due to' locking of the clamp bar 32 against cable 19 has thesame effect of preventing the instantaneous and shock loading of thesafety cable l9;'and instead, the tension load is somewhat graduallyapplied to the safety cable 19 to minimize any likelihood of rupture ofthe safety cable 19.

It will be noted that the clamping shoe end 32.3 of the clamp bar 32 issomewhat rounded at the locations which engage the safety cable 19, andthis rounded shape of the clamping shoe 32.3 provides for at least aslight reduction in the rate of applying the tension loading to thecable 19, and a slight reduction in the rate at which the appliance 21stops along cable 19. The clamp bar 32 must be swung by the expansion ofspring 30 as the rod 29 moves through the lower. frame plate 23 and thismovement is required in order to rotate the clamping shoe 32.3 to thepoint where it will lock against the cable 19. As a result, the need forspring 30 to expand lengthwise contributes materially, along with thecurvature of the clamping shoe 32.3 to reduce the shock loading or therate of application of load to the cable 19. 1 It will therefore berecognized that several phases of the appliance 21 contribute to thereduction of shock fected. When the-repair has been effected, the winchcable 18 need merely be drawn downwardly by the winch 17 to unlock theappliance 21 from cable 19. Thereafter the fixture frame may be raisedand lowered as previously described. v

It will be seen that l have provided a new and improved safetyapparatusfor a tower wherein a winch cable at the bottom of the tower isutilized for lowering and raising the suspension cables extendingupwardly through the tower pole for raising and lowering the fixtureframe which is normally suspended from the top of the tower. The safetyapparatus includes a pair of fixed cables within the pole of the tower,and a gripping mechanism which normally transmits the tension load fromthe winch cable to the suspension cables. The" gripping apparatus willslidably move along the safety cables provided and in response to lossof the tension load between the winch cable and the suspension cables,the safety appliance or gripping mechanism will lock against the safetycable. The gripping mechanism operates to minimize shock loading of thesafety cable and of the suspension cables at the instant the safetydevice locks up against the safety cables and stops the falling of thefixture frame. Although the fixture frame will fall downwardly and thesafety appliance 21 will move upwardly, only a few inches from themoment of failure of the winch cable to the time at which the safetyappliance locks up against the safety cable, the weight of the fixtureframe 13 and the lamps 12 is considerable and can produce a substantialamount of momentum which, but for the present invention, might cause asubstantial shock loading of the suspension cables and possibly of thesafety cable when the suspension cables are quickly locked topreventfalling of the fixture frame.

What is claimed is:

1. Safety apparatus for a tower having a fixture frame to be suspendedfrom pulleys at the top of the tower on suspension cables and lowered bya winch cable extendible upwardly through the tower, the safetyapparatus comprising:

a fixed guide cable extending from top to bottom within the tower;

a connector appliance connected to the winch cable and also to thesuspension cables for transmitting tension load therebetween forsupporting the fixture frame, said appliance having a frame with attachment meansfor securing to the suspension cables and transmittingupward force to the frame; said appliance also including an uprightcable-guiding jaw affixed on the appliance frame and lying along theguide cable;

a clamp bar pivoted on the appliance frame adjacent said upright jaw,one end of the bar forming a clamping shoe confronting the upright jawand cooperating therewith to guide and clamp the cable therebetween, theclamping shoe being swingable upwardly and away from the jaw to releasethe cable, and said shoe being swingable inwardly against the cable toclamp the cable against the jaw;

a fitting connected to the other end of the clamp bar opposite theclamping shoe, and also secured to the winch cable and transmittingdownward force to the bar to hold the clamping shoe out of lockingrelation with the guide cable; and

a compression spring anchored on the appliance frame and urging saidother end of the clamp bar upwardly to swing the clamp bar and urge theclamping shoe against and into clamping engagement with the guide cableand jaw in the event of failure of the winch cable.

2. The safety apparatus according to claim 1 and including a rigid cableguide afiixed on the frame and defining an upright cable passagereceiving the guide cable therethrough, said cable guide defining saidcable-guiding jaw at one side of the passage and also defining atransversely opening slot across from said jaw and receiving theclamping shoe of the clamp bar therein.

3. The safety apparatus according to claim 1 wherein said fittingincludes a rod extending downwardly from the clamp bar and slidablythrough an opening in the frame and attached to the winch cable belowthe frame, the spring encompassing the rod and bearing downwardlyagainst the frame at the periphery of the opening to urge the rod andclamp bar upwardly upon failure of the winch cable.

4. The safety apparatus according to claim 1 and said attachment meansincludes a spring interposed between the frame and each of thesuspension cables to facilitate limited motion between the applianceframe and the suspension cables to minimize the shock effect of quicklystopping the appliance along the affixed guide cable.

5. The safety apparatus according to claim 4 wherein said attachmentmeans includes a plurality of upright attachment rods each slidablyextending throughran opening in the frame and connected to a respectivesuspension cable above the frame and each of the rods having acompression spring encompassing the rod below the respective opening inthe frame, one end of each spring bearing upwardly against the frame atthe periphery of the opening and the other end of the spring urging therod downwardly to allow limited resilient movement between the frame andsuspension cable in response to rapid starting and stopping of relativevertical movement between the frame and suspension cable.

6. The safety apparatus according to claim 1 and a second fixed guidecable extending from top to bottom within the tower, the appliance framehaving guide means receiving and guiding along said second cable andpreventing turning of the appliance in the tower as the appliance isalternately retained against upright movement by the winch cable orfirst-mentioned guide cable. 7

7. Safety apparatus to prevent falling of a towermounted fixture framesuspended on suspension cables trained over pulleys at the top of thetower in the event of failure ofv the winch cable which normally anchorsthe suspension cables against uncontrolled rapid travel upwardly throughthe tower, said safety apparatus comprising:

a pair of fixed guide cables extending from top to bottom within thetower;

a connector appliance connected to the winch cable and also to thesuspension cables for transmitting tension load therebetween forsupporting the fixture frame, said appliance including a pair of spacedrigid frame plates above and below each other in confronting relation,and a plurality of rigid posts affixed to and interconnecting said frameplates, said frame plates having bearing apertures slidably receivingthe guide cables therethrough and in side by side relation to eachother;

a rigid U-shaped clamp body defining a cable-guiding passagetherethrough and along the closed side of the U-shape, said clamp bodybeing affixed to the frame plates with said cable-guiding passagealigned with a pair of the bearing apertures and in embracing relationwith one of the guide cables, said clamp body defining a clamping jawadjacent said passage and at the closed side of the U-shape;

a clamp bar with a cable clamping shoe on one end thereof and extendingtransversely through to the open side of said U-shaped clamp body andinto proximity with the guide cable in said passage, said bar andclamping "shoe extending obliquely upwardly toward the guiding cable andnormally permitting free sliding between the cable and the jaw and shoe,said clamp bar being pivoted to said U- shaped body to permit upwardswinging of the clamping shoe away from the guide cable and downwardswinging of the clamping shoe toward and into locking engagement withthe guide cable to prevent upward movement of the clamp body andconnector appliance along the guide cable, said clamp bar also having anattachment end opposite the clamping shoe;

a slide bar depending from the attachment end of the clamp bar andconnected thereto, said slide bar extending downwardly through anopening in the lower frame plate of the appliance and being slidabletherethrough and said slide bar'being-connected to the depending winchcable;

a compression spring encompassing said slide bar and bearing downwardlyagainst the frame plate at the periphery of the opening therein and alsobearing upwardly on the slide bar to urge the slide bar upwardly and theclamping shoe inwardly into locking relation with the guide cable in theevent of rupture of the anchor cable; and

ing through openings in the upper frame plate, each of said connectorrods extending upwardly from the frame plate and being connected to arespective suspension cable and also having a portion extendingdownwardly from the upper frame plate and embraced by a compressionspring bearing upwardly against the frame plate and downwardly againstthe connector rod for providing resilient yieldability in the connectionbetween the suspension cables in the appliance frame.

8. The safety apparatus according to claim 7 wherein the openings in theupper frame plate and the slidable connector rods extending therethroughare symmetrically and uniformly spaced from each other around theperiphery of the upper frame plate, and the opening in the lower frameplate and the slide bar therein are disposed substantially centrally ofthe lower frame plate.

9. Safety apparatus to prevent falling of a towermounted fixture framesuspended on suspension cables trained over pulleys at the top of thetower in the event of failure of the winch cable which normally anchorsthe suspension cables against uncontrolled rapid travel upward throughthe tower, said safety apparatus comprising a safety cable extendingfrom top to bottom within the tower; and

a gripping mechanism loosely embracing said safety cable and slidabletherealong, said gripping mechanism being connected to the suspensioncables and also to the winch cable and transmitting the tension loadtherebetween, said gripping mechanism having releasable gripping meansto tightly grip and lock onto the safety cable and also having tensionload-responsive operating means resiliently biased to normally cause thegripping means to lock onto the safety cable and said tensionload-responsive operating means also connected to the winch cable andoperated in response to high tension on the winch cable to hold thegripping means in released condition relative to the safety cable and inresponse to loss of such tension load to allow said locking of thegripping means and prevent upward travel of the gripping mechanism andsuspension cables in the tower.

1. Safety apparatus for a tower having a fixture frame to be suspendedfrom pulleys at the top of the tower on suspension cables and lowered bya winch cable extendible upwardly through the tower, the safetyapparatus comprising: a fixed guide cable extending from top to bottomwithin the tower; a connector appliance connected to the winch cable andalso to the suspension cables for transmitting tension load therebetweenfor supporting the fixture frame, said appliance having a frame withattachment means for securing to the suspension cables and transmittingupward force to the frame; said appliance also including an uprightcable-guiding jaw affixed on the appliance frame and lying along theguide cable; a clamp bar pivoted on the appliance frame adjacent saidupright jaw, one end of the bar forming a clamping shoe confronting theupright jaw and cooperating therewith to guide and clamp the cabletherebetween, the clamping shoe being swingable upwardly and away fromthe jaw to release the cable, and said shoe being swingable inwardlyagainst the cable to clamp the cable against the jaw; a fittingconnected to the other end of the clamp bar opposite the clamping shoe,and also secured to the winch cable and transmitting downward force tothe bar to hold the clamping shoe out of locking relation with the guidecable; and a compression spring anchored on the appliance frame andurging said other end of the clamp bar upwardly to swing the clamp barand urge the clamping shoe against and into clamping engagement with theguide cable and jaw in the event of failure of the winch cable.
 2. Thesafety apparatus according to claim 1 and including a rigid cable guideaffixed on the frame and defining an upright cable passage receiving theguide cable therethrough, said cable guide defining said cable-guidingjaw at one side of the passage and also defining a transversely openingslot across from said jaw and receiving the clamping shoe of the clampbar therein.
 3. The safety apparatus according to claim 1 wherein saidfitting includes a rod extending downwardly from the clamp bar andslidably through an opening in the frame and attached to the winch cablebelow the frame, the spring encompassing the rod and bearing downwardlyagainst the frame at the periphery of the opening to urge the rod andclamp bar upwardly upon failure of the winch cable.
 4. The safetyapparatus according to claim 1 and said attachment means includes aspring interposed between the frame and each of the suspension cables tofacilitate limited motion between the appliance frame and the suspensioncables to minimize the shock effect of quickly stopping the applIancealong the affixed guide cable.
 5. The safety apparatus according toclaim 4 wherein said attachment means includes a plurality of uprightattachment rods each slidably extending through an opening in the frameand connected to a respective suspension cable above the frame and eachof the rods having a compression spring encompassing the rod below therespective opening in the frame, one end of each spring bearing upwardlyagainst the frame at the periphery of the opening and the other end ofthe spring urging the rod downwardly to allow limited resilient movementbetween the frame and suspension cable in response to rapid starting andstopping of relative vertical movement between the frame and suspensioncable.
 6. The safety apparatus according to claim 1 and a second fixedguide cable extending from top to bottom within the tower, the applianceframe having guide means receiving and guiding along said second cableand preventing turning of the appliance in the tower as the appliance isalternately retained against upright movement by the winch cable orfirst-mentioned guide cable.
 7. Safety apparatus to prevent falling of atower-mounted fixture frame suspended on suspension cables trained overpulleys at the top of the tower in the event of failure of the winchcable which normally anchors the suspension cables against uncontrolledrapid travel upwardly through the tower, said safety apparatuscomprising: a pair of fixed guide cables extending from top to bottomwithin the tower; a connector appliance connected to the winch cable andalso to the suspension cables for transmitting tension load therebetweenfor supporting the fixture frame, said appliance including a pair ofspaced rigid frame plates above and below each other in confrontingrelation, and a plurality of rigid posts affixed to and interconnectingsaid frame plates, said frame plates having bearing apertures slidablyreceiving the guide cables therethrough and in side by side relation toeach other; a rigid U-shaped clamp body defining a cable-guiding passagetherethrough and along the closed side of the U-shape, said clamp bodybeing affixed to the frame plates with said cable-guiding passagealigned with a pair of the bearing apertures and in embracing relationwith one of the guide cables, said clamp body defining a clamping jawadjacent said passage and at the closed side of the U-shape; a clamp barwith a cable clamping shoe on one end thereof and extending transverselythrough to the open side of said U-shaped clamp body and into proximitywith the guide cable in said passage, said bar and clamping shoeextending obliquely upwardly toward the guiding cable and normallypermitting free sliding between the cable and the jaw and shoe, saidclamp bar being pivoted to said U-shaped body to permit upward swingingof the clamping shoe away from the guide cable and downward swinging ofthe clamping shoe toward and into locking engagement with the guidecable to prevent upward movement of the clamp body and connectorappliance along the guide cable, said clamp bar also having anattachment end opposite the clamping shoe; a slide bar depending fromthe attachment end of the clamp bar and connected thereto, said slidebar extending downwardly through an opening in the lower frame plate ofthe appliance and being slidable therethrough and said slide bar beingconnected to the depending winch cable; a compression springencompassing said slide bar and bearing downwardly against the frameplate at the periphery of the opening therein and also bearing upwardlyon the slide bar to urge the slide bar upwardly and the clamping shoeinwardly into locking relation with the guide cable in the event ofrupture of the anchor cable; and a plurality of sliding connector rodsslidably extending through openings in the upper frame plate, each ofsaid connector rods extending upwardly from the frame plate and beingconnected to a respective suspension cable and also Having a portionextending downwardly from the upper frame plate and embraced by acompression spring bearing upwardly against the frame plate anddownwardly against the connector rod for providing resilientyieldability in the connection between the suspension cables in theappliance frame.
 8. The safety apparatus according to claim 7 whereinthe openings in the upper frame plate and the slidable connector rodsextending therethrough are symmetrically and uniformly spaced from eachother around the periphery of the upper frame plate, and the opening inthe lower frame plate and the slide bar therein are disposedsubstantially centrally of the lower frame plate.
 9. Safety apparatus toprevent falling of a tower-mounted fixture frame suspended on suspensioncables trained over pulleys at the top of the tower in the event offailure of the winch cable which normally anchors the suspension cablesagainst uncontrolled rapid travel upward through the tower, said safetyapparatus comprising a safety cable extending from top to bottom withinthe tower; and a gripping mechanism loosely embracing said safety cableand slidable therealong, said gripping mechanism being connected to thesuspension cables and also to the winch cable and transmitting thetension load therebetween, said gripping mechanism having releasablegripping means to tightly grip and lock onto the safety cable and alsohaving tension load-responsive operating means resiliently biased tonormally cause the gripping means to lock onto the safety cable and saidtension load-responsive operating means also connected to the winchcable and operated in response to high tension on the winch cable tohold the gripping means in released condition relative to the safetycable and in response to loss of such tension load to allow said lockingof the gripping means and prevent upward travel of the grippingmechanism and suspension cables in the tower.